Pulse compression of guided wave by airborne ultrasound excitation for improving defect detection accuracy in concrete

Abstract

Scanning airborne ultrasound source technique has been developed as a safe and simple non-contact non-destructive inspection method. This method enables non-contact excitation of guided waves by using high-intensity airborne ultrasound waves. However, the airborne ultrasound source that can generate high intensity airborne ultrasounds uses resonance drive, so the sound waves are emitted for a long time. As a result, the inspection results become complicated, and the inspection accuracy decreases. To solve this problem, we proposed a pulse compression using chirp signals of guided waves generated by airborne ultrasound. In this paper, we investigated the pulse compression of guided waves generated in mortar samples using an airborne ultrasound source driven by a chirp signal. As a result, it was confirmed that the visualization accuracy of defects was improved by pulse compression.